How Does Machine Espresso Work?

Machine espresso uses precision pressure and mind-blowing filter technology to create the coffee we love. What exactly is it that makes it work?

To make espresso, hot water is forced under high pressure through finely ground coffee. The process is similar to making drip coffee. However the pressure is the major difference.

The Group Head

The group head is the portafilter that you place in the espresso maker when making it. It is responsible for dispersing the water into the portafilter and controlling the pressure that results from the extraction. There are numerous kinds of group heads each with its own advantages and disadvantages. Some are specifically designed for stability of temperature while others are built to handle pre-infusion. Some are designed to control the lever. There are some that have a combination of features, such as the E61, which is the standard choice for many baristas due to its capacity to offer multiple benefits in one package.

As you can see in the above photo the group head comes with several notches to place your portafilter before twisting it manually to lock it in. There is also a gasket made from rubber in the notches and helps to create the seal when you insert your portafilter into the machine. The notches allow for an exact placement of the portafilter. This is crucial to ensure an even extraction.

The group head does not just allow you to put in your portafilter easily, but it also maintains an even temperature. It does this by cycling hot water through the brew pan and around the portafilter, ensuring that it is always at the correct temperature to extract. This is crucial, since even a few degrees can make the difference between good and great commercial espresso machine.

The Pump

The motorized pumps that are used in rotary espresso machines supply the nine atmospheric bar pressure that is required for espresso coffee machine uk extraction. This differs from manual piston machines that use levers. This pressure builds up by removing tap water from a reservoir, and pumping it through a heat exchanger before being shot through the ground coffee inside the group head.

Pumps tend to be less expensive and last longer than piston-driven machines. However, both types of machines can degrade due to excessive use and insufficient cleaning. They also increase the complexity of mechanical systems and can lead to a high price tag on even the most basic models.

Some espresso machines make use of steam pressure instead of a pump to brew espresso. The disadvantage of this is that the same boiler that produces steam also raises the temperature of the water until it reaches boiling, which can lead to over-extraction. Additionally, these machines frequently have to rebuild their pressure between cups, which takes time and energy.

Many espresso machines use the rotary or vibration pump. A vibration model makes use of the vibrating disk to create pressure, while the rotating model pushes hot water through the ground at a high speed. Both types of machine can produce an excellent espresso, however rotary machines are quieter and more durable than vibration pumps.

The Boiler

The boiler is used to heat the water to the right temperature for extraction. The steam produced will eventually reach the portafilter, which contains the espresso coffee grounds. It is then funneled into the cup. During this process, the steam creates pressure to push through the grounds of the coffee machine espresso. This creates a layer crema on top. This is one of the main characteristics of a good espresso.

There are three distinct types of espresso machines, each with different pumps and brew temperature. There are a variety of ways to control the brew as well as the size of cup that can be produced by the machine.

The first espresso machines were steam-based. They utilized one boiler to create both steam and brew but the pressure they could generate was low - only two bars of atmospheric pressure maximum. This resulted in the coffee tasting bitter and burnt. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni developed the modern espresso machine.

The most commonly used espresso machine is a semiautomatic with an electric pump. When people think of espresso machines, they think of these machines. Semi-automatic machines require you to grind and tamp the beans yourself The pump, however, regulates the flow of water and pressure. This is a great compromise between the human touch and the mechanized quality.

The Filter

Typically, espresso machines utilize a filter to separate out the coffee grounds as they pass through the hot water. The filter is also a crucial part of the temperature control system as it prevents the machine from overheating.

It also aids in flavor, as it allows for a more prolonged bloom time. This allows beans to let their nuances out and provides an opportunity to improve extraction.

It is important to remember that even the most efficient filter can produce a bad cup of coffee. The quality of the beans as well as the extraction, are still very important.

This is where the magic happens, it's what makes espresso taste great. The grouphead, also called the brew head, is the place where the portafilter (the thing you put the coffee ground into) is placed when you're making espresso.

In a steam-driven espresso machine, hot water is heated in an airtight tank to create steam. Steam is then pushed through the grounds at high pressure. These types of machines are usually less expensive and easier to maintain than pumps-driven models. They are however limited in their ability to create the ideal brewing conditions as they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed-air-pump-driven espresso machines have been gaining popularity. They use an air-compressor to force hot water through the ground and are much more mobile than steam-driven electric espresso machines.